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South West Deeps (East) MPA

Status: Marine Conservation Zone (MCZ)

The site is located in the Western Channel and Celtic Sea region, next to the South-West Deeps (West) MCZ. The eastern boundary of the site is approximately 190 km south-west of the Land’s End peninsula.


South West Deeps (East) MCZ is located in the Western Channel and Celtic Sea region with the eastern boundary approximately 190 km south-west of the Land’s End peninsula. The seabed is dominated by Subtidal sand with areas of Subtidal coarse sediment throughout and an area of Deep-sea bed in the south. The depth of the site reaches 750 m, and the variety of habitats between 150 and 170 m support a range of species.

The site covers an area of 4,676 km2 and contributes the greatest area of Subtidal sand to the MPA network within this regional sea. It is home to a range of species such as flat fish (sole and plaice) and clams, cockles and marine worms which burrow within the sand. The site also protects Subtidal coarse sediment, the geological feature Celtic Sea Relict Sandbanks and Deep-sea bed. The Celtic Sea Relict Sandbanks are among the largest and deepest shelf sand ridges in UK waters. Additionally, the site is one of only two MPAs outside of Scotland’s waters to protect Deep-sea bed habitats beyond the shelf break.

More detailed site information can be found in the Summary section below.

Map displaying the South West Deeps (East) MPA boundary and associated protected feature data. Visit JNCC's MPA Mapper to further view and explore data for this MPA.

Map showing South-West Deeps (East) Marine Protected Area and linking to the MPA mapper


Legislation behind the designation: Marine and Coastal Access Act (2009)


Protected Features

 Protected Feature Feature Type
Celtic Sea Relict Sandbanks Feature of Conservation Importance
Deep-sea bed Broad-scale habitat
Subtidal coarse sediment Broad-scale habitat
Subtidal sand Broad-scale habitat

Specific information on the conservation objectives related to this site is provided in the Conservation Advice section.

The acquisition of new data may result in updates to our knowledge on feature presence and extent within this site. The most up-to-date information is reflected on the map on this page and in JNCC’s MPA Mapper and the evidence underpinning this can be viewed in the Monitoring and Evidence section.


Site Timeline

The diagram below is a summary of the key milestones involved in the selection and designation of the South West Deeps (East) MCZ. More detail can be found within the Relevant Documentation section and in the post-consultation advice

September 2011
Regional projects recommended a total of 127 rMCZs to Defra and the SNCBs. South West Deeps (East) MCZ was proposed by the Finding Sanctuary Regional Project.
June 2018 – July 2018
South West Deeps (East) MCZ included in formal public consultation on Tranche Three MCZs.
May 2019
Tranche three designations announced – South West Deeps (East) MCZ designated.


Relevant Documentation

The documents referred to below and any other historical documents relating to South West Deeps (East) MCZ were produced during the selection and designation process and therefore may be out of date. This Site Information Centre is the most up-to-date source of information for this MPA, and will reflect any additional information gathered since these documents were produced. Further information about the Marine Conservation Zone site selection process and historic MCZ advice is available on JNCC's MCZ webpage.

  • South West Deeps (East) MCZ Designation Order –the official description of the site designation under the Marine and Coastal Access Act 2009. The Designation Order includes boundary co-ordinates, Conservation Objectives and a list of the designated features. More information on the designation, including a designation map and factsheet is available on Defra's website.
  • JNCC's pre- and post-consultation scientific advice for features proposed for designation in 2019.
  • JNCC's formal conservation advice for this site is available in the Conservation Advice section.



Last updated: June 2020

Information for this site summary was adapted from JNCC’s scientific advice to Defra on South West Deeps (East) MCZ and incorporates any further information gathered since the advice was produced. Please refer to the Relevant Documentation section for further details and information sources.


Site overview

This expansive offshore site covers an area of 4,676 km2 and reaches depths of 750 m. It protects several broad-scale habitats including Subtidal sand, Subtidal coarse sediment, Deep-sea bed, and the geological feature Celtic Sea Relict Sandbanks. The seabed is characterised by the largest area of Subtidal sand protected within any MPA within the Western Channel and Celtic Sea region, with areas of Subtidal coarse sediment and the deep, long shelf sand ridges of the Celtic Sea Relict Sandbanks. In the southern half of the site the Deep-sea bed feature dominates; these habitats can be hard substrates or sedimentary, supporting an array of different marine species compared to similar habitats in shallower regions. The Subtidal sand and coarse sediments are supporting habitat for species such as flat fish (sole and plaice) on the seabed surface, and species of cockles, marine worms and clam which burrow within the sand itself.

South West Deeps (East) MCZ was recommended by the Finding Sanctuary regional MCZ project for broad-scale habitats. Data have been provided through the BGS seabed sediment PSA dataset and Marine Recorder which were used to create the habitat map produced by EUSeaMap (2012). MB0102 Task 2A provided a habitat map of the geological feature Celtic Sea Relict Sandbanks. The original boundary proposed by Finding Sanctuary was adjusted to reduce the socio-economic impact on commercial fishing, specifically non-UK fleets. The site now borders with the existing South West Deeps (West) MCZ.

Further detail on the evidence for this MCZ can be found in the Monitoring and Evidence section.

Site location: Co-ordinates for this MCZ can be found in the Designation Order listed in the Relevant Documentation section.

Site area: 4,676 km2 (bigger than the entire Cornish county).

Site depth range: 150–750 m.

Charting Progress 2 Biogeographic Region: Western Channel and Celtic Sea.

Site boundary description: The site is a simple polygon with eight boundary lines running south-west to north-east in line with the guidance provided by the MCZ project Ecological Network Guidance (ENG). The polygon is delineated at the southern and eastern edges by the Exclusive Economic Zone. Following pre-consultation advice the boundary of the site was amended to reduce socio-economic impact on commercial fishing.


Monitoring and Evidence

Last updated: November 2023

Site-specific data

There are a range of data that underpin this MCZ. The full overview of these data used to support site identification along with information on confidence in feature presence and extent is available in JNCC’s Tranche Three MCZ pre-consultation and post-consultation scientific advice for offshore Marine Conservation Zones proposed for designation in 2019. Due to the modified boundary the full assessment of this site can be found in the post-consultation scientific advice report. JNCC will be adding relevant survey data for this MPA to its MPA Mapper in due course.

Some of the data for this MCZ have been collected through JNCC-funded or collaborative surveys and some through other means. Data from these surveys provide direct evidence confirming the presence of the protected features within the site.


Knowledge Gaps

As part of the UK Marine Monitoring and Assessment Strategy (UKMMAS), JNCC led the development of a UK Marine Biodiversity Monitoring Strategy, working with partners across the UK monitoring community. The Strategy spans UK territorial and offshore waters, focusing on biodiversity in the wider environment and within Marine Protected Areas.  Its aim is to implement efficient, integrated monitoring of marine biodiversity to provide the evidence needed for all the UK's policy drivers.

The evidence collected during MPA monitoring surveys is used in combination with other available evidence to:

  • Enable assessment of condition of the features within sites;
  • Contribute to the assessment of the degree to which management measures are effective in achieving the conservation objectives for the protected features;
  • Support the identification of priorities for future protection and/or management; and,
  • Enable Government to fulfil its national and international assessment and reporting commitments in relation to MPAs and help identify where further action may be required.

More detail on offshore MPA monitoring can be found on the Offshore MPA monitoring webpage. A list of monitoring surveys and relevant reports can be found on the MPA monitoring survey reports webpage.

If you are aware of any additional data not listed here or scientific papers relevant to this site, please contact us.


Conservation Advice

Last updated: January 2021

Updated formal conservation advice for this MPA was produced in January 2021. Further information on JNCC’s approach used to develop conservation advice packages is available on our 'Conserving MPAs' webpage along with a Glossary of Terms used in JNCC conservation advice and a short video explaining how to use the conservation advice packages.

You must refer to this advice if you:

  • undertake an MCZ assessment for a plan or project that could impact the site;
  • provide information for such an assessment;
  • respond to specific measures to further the conservation objectives for the site; and 
  • consider the need to put new or additional management measures in place.

You may also find it useful to refer to this advice if you:

  • carry out any other activity that could impact the site.

We will engage with stakeholders to identify any lessons which JNCC can learn from customers who have used the advice, with a view to continuing to ensure it is fit-for-purpose.

The following table provides an overview of the components of the conservation advice, and provides hyperlinks to each of the products for this MPA.  These elements together form JNCC’s formal conservation advice for this site and should be read in conjunction with each other.  This advice reflects the most up-to-date evidence held by JNCC (correct as of January 2021).  

Document Overview
Background Information Explains the purpose of the advice and when it must be referred to.

Conservation Objectives

Supplementary Advice on the Conservation Objectives (SACO)

The Conservation Objectives set out the broad ecological aims for the site. JNCC provides supplementary advice in the SACO which is essential reading to support interpretation of these conservation objectives.

You can use these documents to assess the impacts of your planned activity on the important attributes of the site.

Conservation Advice Statements These statements provide a summary of the Supplementary Advice on the Conservation Objectives (SACO).
  • Site condition presents our up-to-date understanding of the condition of features within the site;
  • Conservation benefits which the site can provide, these help you understand what is important about the site and why it needs protecting; and
  • Conservation measures which JNCC considers are needed to support achievement of the conservation objectives. These provide clarity around measures needed to support restoration or maintenance of the feature(s) within the site.
Advice on Operations

Provides information on the activities capable of affecting site integrity and therefore achievement of the site’s conservation objectives.

This is a starting point for determining potential management requirements. It does not take into account the intensity, frequency or cumulative impacts from activities taking place. It is simply to advise you of the possible adverse impacts that your activity can have on a MPA’s features.

Use the advice on operations to determine those pressures your activity causes that could harm the habitat and/or species features of the site.

These documents are available on JNCC's Resource Hub.  



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